Cryo-EM structure of the Blastochloris viridis LH1–RC complex at 2.9 Å
| Autor: | Daniel P. Canniffe, C. Alistair Siebert, Pu Qian, Peiyi Wang, C. Neil Hunter |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular 0301 basic medicine Protein Conformation Cryo-electron microscopy Light-Harvesting Protein Complexes medicine.disease_cause Ring (chemistry) 03 medical and health sciences chemistry.chemical_compound Protein structure Bacterial Proteins Benzoquinones medicine Magnesium Photosynthesis Bacteriochlorophylls Hyphomicrobiaceae Binding Sites Multidisciplinary 030102 biochemistry & molecular biology Protein Stability Chemistry Blastochloris viridis Cryoelectron Microscopy Resolution (electron density) Quinone Folding (chemistry) Crystallography 030104 developmental biology Bacteriochlorophyll Apoproteins |
| Zdroj: | NATURE |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/s41586-018-0014-5 |
| Popis: | The light-harvesting 1–reaction centre (LH1–RC) complex is a key functional component of bacterial photosynthesis. Here we present a 2.9 Å resolution cryo-electron microscopy structure of the bacteriochlorophyll b-based LH1–RC complex from Blastochloris viridis that reveals the structural basis for absorption of infrared light and the molecular mechanism of quinone migration across the LH1 complex. The triple-ring LH1 complex comprises a circular array of 17 β-polypeptides sandwiched between 17 α- and 16 γ-polypeptides. Tight packing of the γ-apoproteins between β-polypeptides collectively interlocks and stabilizes the LH1 structure; this, together with the short Mg–Mg distances of bacteriochlorophyll b pairs, contributes to the large redshift of bacteriochlorophyll b absorption. The ‘missing’ 17th γ-polypeptide creates a pore in the LH1 ring, and an adjacent binding pocket provides a folding template for a quinone, Q P, which adopts a compact, export-ready conformation before passage through the pore and eventual diffusion to the cytochrome bc 1 complex. |
| Databáze: | OpenAIRE |
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